The invention relates to a power grinder.
From British Patent GB 23 22 582, a pivotable pincer with a grinding plate for holding grinding sheets is known; the grinding sheet is braced with its back against the underside of the grinding plate and can be firmly clamped to its top.
For firmly clamping the grinding sheet, the user has to use both hands, and if at all possible the power tool should be placed on a firm support. One end of the grinding sheet has to be introduced with one hand into a slot between an opened clamping jaw and the top side of the grinding sheet holder, while the clamping jaw has to be kept open in the release position with the other hand until the grinding sheet end has been introduced. Once the clamping jaw is let go, it then closes by spring force and assumes its clamping position, in which it firmly clamps the end of the grinding sheet in a manner in which it is secured against being lost. The grinding sheet is automatically retightened to a certain degree in the process, in that the rotatably suspended clamping jaw rolls away from the end of the grinding sheet and carries it with it in the process—because of the skewed contact-pressure face on the top of the grinding sheet holder.
For clamping the other end of the grinding sheet, the above-described steps are to be repeated. The attainable clamping force and retightening force are relatively limited, so that a relative motion that occurs during operation of the grinding tool between the grinding sheet holder and the grinding sheet lessens the machining capacity in grinding and limits the service life of the grinding sheet.